US3811739A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brake system with skid control
Assignee: Toyota Motor Corp
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Filing: 1971-08-05
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Granted: 1974-05-21
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Expires: 1991-08-05
Abstract
Abstract In the apparatus disclosed a wheel velocity detector detects the velocity of a wheel on a vehicle that is being slowed down by a brake. A control circuit constrains a pressure regulator to decrease the pressure in the brake fluid that applies the braking force when the control circuit determines that skidding becomes likely. In the control circuit the velocity detector charges a capacitor to a reference velocity level just below the wheel velocity level. A first adjusting circuit allows the capacitor to discharge at a maximum first rate. Thus if the wheel velocity decreases beyond that maximum deceleration rate the wheel velocity may become less than the reference level. A comparator responsive to the wheel velocity detector and the capacitor level responds to the reference level exceeding the wheel velocity level by issuing a pressure reducing pulse to the pressure regulator. The pulse actuates a second adjusting circuit that increases the discharge rate of the capacitor for a given period of time. Thereafter the second adjusting circuit is inactivated and the first rate is reestablished. When, as a result of reduced pressure and braking force, the wheel velocity increases beyond the decreasing reference velocity the pressure reducing pulse ends. A third adjusting circuit measures a period of time from the onset of the pulse longer than the beforementioned time period to reestablish the second rate of discharge after the reestablishment of the first rate, in the event that the wheel velocity level does not exceed the reference level by that time. A setting circuit responds to the cessation of the pressure reducing pulse by momentarily discharging the capacitor to reestablish the differences between the wheel velocity level and the reference level.
Inventors
- 👤 J Ohta
- 👤 A Nakamura
- 👤 H Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:46
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/72; B60T8/17; B60T8/176; B60T8/1763; B60T8/17633; B60T8/58
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
156 words
A brake force modulating apparatus for issuing signals to vary the braking force applied by a brake to a wheel in response to the wheel velocity, comprising comparator means responsive to the velocity of the wheel and to a reference level representing a reference velocity for issuing a first brake varying signal during a first relationship between the reference velocity and the wheel velocity and a second brake varying signal during a second relationship between the reference velocity and the wheel velocity, reference level establishing means responsive to said comparator means and forming an input to said comparator means for establishing the level and varying it with the wheel velocity at a maximum first rate in one direction during the first relationship and at a second rate during a predetermined fixed period of time after the start of the second relationship and a third rate during the second relationship at the conclusion of the predetermined period.
Claim 2
Dependent Claim
156 words
A brake force modulating apparatus for issuing signals to vary the braking force applied by a brake to a wheel in response to the wheel velocity, comprising comparator means responsive to the velocity of the wheel and to a reference level representing a reference velocity for issuing a first brake varying signal during a first relationship between the reference velocity and the wheel velocity and a second brake varying signal during a second relationship between the reference velocity and the wheel velocity, reference level establishing means responsive to said comparator means and forming an input to said comparator means for establishing the level and varying it with the wheel velocity at a maximum first rate in one direction during the first relationship and at a second rate during a predetermined fixed period of time after the start of the second relationship and a third rate during the second relationship at the conclusion of the predetermined period.
Claim 3
Dependent Claim
37 words
An apparatus as in claim 1, wherein said reference level establishing means includes level changing means for establishing a fourth rate after a second predetermined fixed time period has elapsed since the onset of the second relationship.
Claim 4
Dependent Claim
26 words
An apparatus as in claim 2, wherein the third rate is equal to the first rate and the fourth rate is equal to the second rate.
Claim 5
Dependent Claim
47 words
An apparatus as in claim 1, wherein said reference level eStablishing means includes maintaining means for maintaining the reference level at a predetermined relation to the wheel velocity when the wheel velocity varies less than the first maximum rate in the one direction during the first relationship.
Claim 6
Dependent Claim
37 words
An apparatus as in claim 4, wherein said reference level establishing means includes level changing means for establishing a fourth rate after a second predetermined fixed time period has elapsed since the onset of the second relationship.
Claim 7
Dependent Claim
20 words
An apparatus as in claim 4 wherein said reference level establishing means includes information storage means for establishing the level.
Claim 8
Dependent Claim
30 words
An apparatus as in claim 6, wherein said reference level establishing means includes first information adjusting means for changing the level in said storage means at the maximum first rate.
Claim 9
Dependent Claim
37 words
An apparatus as in claim 7, wherein said establishing means includes second adjusting means responsive to said comparator means for causing said information storage means to change at the second rate upon issuance of the second signal.
Claim 10
Dependent Claim
36 words
An apparatus as in claim 8, wherein said second adjusting means includes timing means for actuating said second adjusting means to cause said information storage means to change at the second rate for the given time.
Claim 11
Dependent Claim
32 words
An apparatus as in claim 9, wherein said establishing means includes adjusting means for establishing a fourth rate after a second predetermined fixed time period greater than the first given time period.
Claim 12
Dependent Claim
14 words
An apparatus as in claim 10, wherein said third adjusting means includes timing means.
Claim 13
Dependent Claim
36 words
An apparatus as in claim 11, wherein said reference level establishing means includes level changing means for establishing a fourth rate after a second given time period has elapsed since the onset of the second relationship.
Claim 14
Dependent Claim
41 words
An apparatus as in claim 4, wherein said establishing means includes setting means responsive to the onset of said first signal in said comparator for adjusting the level to the predetermined relationship so said maintenance means may maintain the given relationship.
Claim 15
Dependent Claim
37 words
An apparatus as in claim 13, wherein said reference level establishing means includes level changing means for establishing a fourth rate after a second predetermined fixed time period has elapsed since the onset of the second relationship.
Claim 16
Dependent Claim
58 words
An apparatus as in claim 14, wherein said establishing means includes first information adjusting means for changing the level of said storage means at the first rate, wherein said establishing means includes second adjusting means responsive to said comparator means for causing said information storage means to change at the second rate upon issuance of the second signal.
Claim 17
Dependent Claim
36 words
An apparatus as in claim 4, wherein said reference level establishing means includes level changing means for establishing a fourth rate after a second given time period has ealpsed since the onset of the second relationship.
Claim 18
Dependent Claim
20 words
An apparatus as in claim 1, wherein said reference level establishing means includes information storage means for establishing the level.
Claim 19
Dependent Claim
30 words
An apparatus as in claim 17, wherein said reference level establishing means includes first information adjusting means for changing the level in said storage means at the maximum first rate.
Claim 20
Dependent Claim
37 words
An apparatus as in claim 18, wherein said establishing means includes second adjusting means responsive to said comparator means for causing said information storage means to change at the second rate upon issuance of the second signal.
Claim 21
Dependent Claim
22 words
An apparatus as in claim 19, wherein said first and second adjusting means coact to change the level of said storage means.
Claim 22
Dependent Claim
38 words
An apparatus as in claim 19, wherein said second adjusting means includes timing means for actuating said second adjusting means to cause said information storage means to change at the second rate for the given predetermined fixed time.
Claim 23
Dependent Claim
33 words
An apparatus as in claim 21, wherein said establishing means includes third adjusting means For establishing a fourth rate after a second given time period greater than the first predetermined fixed time period.
Claim 24
Dependent Claim
14 words
An apparatus as in claim 22, wherein said third adjusting means includes timing means.
Claim 25
Dependent Claim
24 words
An apparatus as in claim 22, wherein said second and third adjusting means include logic means for jointly operating on said information storage means.
Claim 26
Dependent Claim
15 words
An apparatus as in claim 17, wherein said information storage means includes energy storage means.
Claim 27
Dependent Claim
58 words
An apparatus as in claim 25, wherein said establishing means includes first energizing means for changing the level of the energy in said storage means at the maximum first rate, wherein said establishing means includes second deenergizing means responsive to said comparator means for deenergizing said storage means at the second rate upon issuance of the second signal.
Claim 28
Dependent Claim
59 words
An apparatus as in claim 26, wherein said first and second deenergizing means coact to reduce the level of the storage means and wherein said second deenergizing means includes timing means for actuating said second deenergizing means to cause the level stored in said energy storage means to reduce at the second rate for the predetermined fixed time period.
Claim 29
Dependent Claim
32 words
An apparatus as in claim 27, wherein said establishing means includes third deenergizing means for establishing the fourth rate after the second predetermined fixed time period greater than the first time period.
Claim 30
Dependent Claim
34 words
An apparatus as in claim 1, wherein the first relationship is such that the wheel velocity exceeds the reference velocity and the second relationship is such that the reference velocity exceeds the wheel velocity.
Claim 31
Dependent Claim
19 words
An apparatus as in claim 29, wherein the level decreases at the maximum first rate and the second rate.
Claim 32
Dependent Claim
27 words
An apparatus as in claim 30, wherein said establishing means includes maintaining means for maintaining the reference voltage at a predetermined level less than the wheel velocity.
Claim 33
Dependent Claim
17 words
An apparatus as in claim 31, wherein said establishing means includes a capacitor for storage of information.
Claim 34
Dependent Claim
112 words
An apparatus as in claim 32, wherein said establishing means includes level changing means connected to said capacitor for establishing a fourth rate after the second given time period has elapsed since the onset of the second relationship, first charge reducing means for reducing the level of the charge on the capacitor at the maximum first rate, second charge reducing means responsive to said comparator means for reducing the charge across the capacitor at a second rate upon issuance of the second signal, and timing means for actuating said second reducing means to cause the charge across the capacitor means to reduce at the second rate for the predetermined fixed time period.
Claim 35
Dependent Claim
16 words
An apparatus as in claim 1, wherein the third rate is equal to the first rate.
Claim 36
Dependent Claim
167 words
A brake system comprising brake application means for applying a brake force to a wheel of a vehicle, brake force modulating means interposed between the braking means and the wheel, said modulating means including wheel velocity indicating means for producing a signal corresponding to the wheel velocity, comparator means in said modulating means responsive to the wheel velocity indicating means and to a reference level representing a reference velocity for issuing a first brake varying signal during a first relationship between the reference velocity and the wheel velocity and a second brake varying signal during a second relationship, reference level establishing means responsive to said comparator means and to said wheel velocity indicating means for establishing the level and varying it with the signal from the wheel velocity indicating means at a maximum first rate in one direction during the first relationship and at a second rate during a predetermined fixed period of time after the start of the second relationship and at a third rate thereafter.
Claim 37
Dependent Claim
167 words
A brake system comprising brake application means for applying a brake force to a wheel of a vehicle, brake force modulating means interposed between the braking means and the wheel, said modulating means including wheel velocity indicating means for producing a signal corresponding to the wheel velocity, comparator means in said modulating means responsive to the wheel velocity indicating means and to a reference level representing a reference velocity for issuing a first brake varying signal during a first relationship between the reference velocity and the wheel velocity and a second brake varying signal during a second relationship, reference level establishing means responsive to said comparator means and to said wheel velocity indicating means for establishing the level and varying it with the signal from the wheel velocity indicating means at a maximum first rate in one direction during the first relationship and at a second rate during a predetermined fixed period of time after the start of the second relationship and at a third rate thereafter.
Claim 38
Dependent Claim
38 words
A brake system as in claim 35, wherein said reference level establishing means includes level changinG means for establishing a fourth rate after a second predetermined fixed time period has elapsed since the onset of the second relationship.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |